Static controller



- W 195351 E. L. MGCLURE S TAT I C G ONTROLLER Filed Jan. 50, 1955 2 Sheets-Sheet l fiv/y/r/"g. 64 @951 I April 9, 19356 E. I... MccLuRE 1,997,224

STATIC CONTROLLER Filed Jan. 30, 1935 2 Sheets-Sheet 2 flvkavl 620195 Patented Apr. 9, 1935 UNITED STATES PATENT ()FFICE of one-half to Joseph Christi, Tex.

E. Garrett, Corpus Application January 30, 1933, Serial No. 654,311

8 Claims.

This invention is an apparatus designed to suppress, reduce, eliminate or otherwise control interfering frequencies which are present in received radio signal energy due to atmospheric conditions, and static due to manufacturing operations such as arc welding, the operation of brush motors and the like. It is well known that interference of the character above set forth is caused by waves of highly damped form and which, therefore, are not restricted to any definite or particular frequency. This makes it difficult, if not impossible, to eliminate such disturbances in a receiving circuit by utilization of a simple filter circuit tuned to a particular frequency. Such means, while eliminating a certain definite frequency from the incoming signal energy, is not capable of effectively handling the band of frequencies which is present incident to the damped character of the interfering energy.

With this in mind I have perfected an apparatus which is designed particularly to suppress, eliminate or otherwise control the interfering band of frequencies immediately above and below a given carrier wave, together with means for controlling said apparatus in a manner such that regardless of the carrier wave to which a receiving set, with which my apparatus is associated, is tuned, the apparatus is effective to suppress or eliminate the interfering frequencies incident to said carrier wave.

With these objects in mind the invention consists in certain new and improved combinations of circuits and means for adjusting the same, and is described in detail in the following specification and claimed in the appended claims.

In the drawings I have illustrated a preferred embodiment of my invention, wherein Figure 1 illustrates a plan View of my apparatus as embodied in a working organization, certain parts being shown in section.

Fig. 2 is a sectional view of the variable in ductance unit.

Fig. 3 is a circuit diagram of my invention in its simplest form. V

Fig. 4 is a circuit diagram of a more improved arrangement of my apparatus, and

Fig. 5 is a circuit diagram of my invention as connected to a conventional receiver.

Referring to Figs. 1 and 2, it will be noted that in a preferred form of my invention I employ a suitable base 1 upon which I mount in any suitable manner the inductance and capacity units of my improved apparatus. The

' inductance unit comprises a stationary'element 2 and a movable element 3. Upon the stationary unit I have wound three axially spaced inductances indicated by the reference characters L L and L These coils are preferably of the same or substantially the same number of turns and are spaced axially from each other on the core 2 a distance substantially equal to the axial dimension of the coils.

The coil L is utilized in the present embodiment of my invention as the input coil or primary,

energizing coil and as such is preferably provided with a plurality of taps indicated at 4, said taps being connected to an adjustable switch member 5 mounted on the panel 6, this arrangement being that commonly used for varying the effective number of convolutions of an input coil in the antenna circuit of the receiving set. One terminal lead of the coil L is connected to the wiper arm 6 of the switch element 5 by the lead wire 1, and also to one set of plates of the variable condenser hereinafter referred to, by the lead wire 8. The other terminal lead of the coil L is connected to the opposite set of plates of the condenser C by the lead wire 9. The inductance coil L has its terminal leads connected respectively to opposite plates of the condenser C by the lead wires l0 and H, and the terminal leads of the coil L are connected to opposite plates of the condenser C by the lead wires 12 and 13.

The movable element of the inductance unit comprises a core member 3 mounted concentrically within the core member 2 and arranged to be axially adjusted within the core member 2 by mechanism to be hereinafter fully described. As shown in Fig. 2 of the drawings, core member 3 is provided with axial y spaced coils L L and L The coils L L and L are preferably of the same or substantially the same number of turns, which may be of the same or substantially the same numberof convolutions as are present in the coils L L and L Preferably the coils L L and L should be of slightly less inductance than the coils L L L and for this reason they may have slightly fewer turns than the coils L L L or the coils L L L may have a diameter relative to that of the coils L L I. such that this condition exists even though the L L L and L L L coils have the same or substantially the same number of turns.

The terminal leads of the coil L are connected by lead wires 14 and iii to the opposite plates of the condenser C and the terminal leads of the coil L are connected to the opposite plates of the condenser C by lead wires l5 and M, respectively. The terminal lead of the coil L is connected by lead wires 18 and l to suitable binding posts 20 and 2|, respectively, suitably mounted upon the base member I. The coil L thus serves as the output coil of my apparatus and is connected to a receiver in a manner to be hereinafter more fully described. A second set of binding posts indicated by the reference characters 22 and 23, respectively, is provided, and these are connected by lead wires 24 and 25 with the condenser C Thus the antenna and ground connections of an aerial system may be connected to the binding posts 22 and 23 and the posts 26 and 2t connected to the antenna and ground connections of a conventional receiving set, to operatively associate my apparatus with a receiver.

The condensers C C C C and C are preferably aligned axially and connected by a common insulated shaft 25 so that they may be simultaneously adjusted or tuned by means of the knob 27 secured to the shaft 25. The condensers are preferably of the same or substantially the same capacity, and in order to make individual adjustments of said condensers for the purpose of adjusting'their relative capacities, small balanc ing condensers such as indicated by. reference characters 0 c 0 c and 0 respectively, may be connected to the large variable condensers C C C C C respectively. By this means/the condensers associated with the coils L L L can be adjusted with respect to said coils in order to provide filter circuits which are resonant to frequencies somewhat above that to which the antenna or input circuit is resonant for any given relative position of the elements of the condensers C C C etc., whereas condensers c and 0 may beadjusted with respect to coils L and L to provide filter circuits which are resonant to frequencies slightly below the frequency to. which the antenna or input circuit including coils L and L is resonant. It is apparent, therefore, that by having the condensers C to C inclusive, simultaneously adjustable to tune the circuits with which they are associated, the input circuit including the coils L and L and the adjustable condenser C, may be tuned to resonance with a given signal frequency and simultaneously the several filter circuits L --C L -C L -C L C are similarly tuned so that the bands of interfering frequencies which they are designed to suppress are shifted to positions respectively, above and below that of the incoming signal frequency. Thus the filter circuits are always tuned with'the input circuit to resonance with bands of interfering frequencies lying immediately above and below the incoming signal.

, 'Referring further to Fig. 2 of the drawingsit will be seen that the inductance element of my apparatus is provided with means for axially shifting the movable core member with reference to the stationary core member. Said means comprises a shaft 28 supported at one end in the panel i5 and at the opposite end in a suitable primary and secondary coils. For so moving the movable core member I provide a screwthreaded shaft 33 rotatably mounted at one end in a bearing 3! associated with the panel 6, and at its opposite end in a suitable bearing provided in the bracket 29. The shaft 38 has screw-threaded engagement with the end walls of the movable core member and the forward end of the shaft 1 protrudes through the panel 5 and is provided with a gear member 82. The gear member 32 is fastened to the shaft 3i! and is arranged to mesh with an internally threaded controlknob 33 mounted upon the shaft 28. The gear ratio be tween the internal gear on the knob member 33 and the gear 32 is such'that by a complete, or substantially complete, rotation of the knob'member 33, the core member 3 is caused to make a complete axial excursion within the secondary core member 2. v

I also find it desirable to provide a metallic shield for my apparatus such as indicated at S,

,such shield being preferably made in the form of a container within which my entire apparatus may be housed, as clearly shown in Figs. 1 and 2.

Referring to Fig. 3 of the drawings, I'have shown a simple circuit diagram of my invention showing the relationship of the primary and secondary inductance coils and the variable con- .densers. It is here to be noted that the energizwith means being diagrammatically shown for simultaneously adjusting the a several condensers and for shifting the movable coils with reference to the stationary coils. 'This figure also shows diagrammatically the tapped connections to the primary coil L Fig. 5 shows diagrammatically the circuit arrangement when my improved apparatus is connected to a conventional receiver. It has been found in actual practice that it is advisable to make theconnection between my apparatus and a set having the usual antenna coil'3 l at a point between said coil and the first tube of the set for the reason that to include this coil in a circuit would place too much inductance in the input circuit. For, this reason I find it desirable to either remove entirely or disconnect from the circuit, the antenna coil found in many of the present day receivers. Y

In operation, after having connected my apparatus to a receiver in the manner hereinbefore set forth, I proceed to tune the receiver to a desired. station with the movable core member of the inductance element of my apparatus substantially centered axially with respect to the stationary element thereof. The knob 2'! is then 7 manipulated .to obtain a maximum degree of volume in the reproducer, whereupon the knob 33 is vmanipulated to shift the movable. core member 3 axially with reference to the stationary core member 2. This shifts the phase relation of the filter circuits until the interfering frequencies are suppressed or eliminated, and in view of the fact that the antenna circuit is maintained tuned to the desired signal frequency, I obtain a complete or substantial elimination of interfering frequencies while maintaining substantially full volume for the received signal.

It is important to note that in View of the inultiplicity of filter circuits employed and the manner in'which they are inductively associated with each other, my apparatus is capable of suppressing a far greater number of interfering frequencies than has heretofore been possible in wave filters of conventional design. For instance, the wave filter circuits-will be resonant to individual frequencies, and by their inductive and capacity coupling one with another, they will provide additional circuits being resonant to slightly different frequencies, so that by considering all possiblecombinations of the several individual filter circuits with'one another, it will be readily apparent that by thejparticular association of the circuits I employ, I am able to provide filter circuits resonant to a very great number of slightly difierent frequencies above and below the signal to 'be received. Another important element in the successful functioning of my apparatus I believe to be the novel arrangement of primary and secondary circuits with the inherent 180 phase displacement therebetween and the series inductance input circuit including two primary circuits each having tuned secondary trap circuits inductively coupled thereto, and the primary inductance circuits being also inductively coupled. This arrangement is highly effective in covering a very substantial range of damped waves on either side of the signal desired, and it is possible to vary the extent or degree of concentration of frequencies within these ranges by axially shifting the secondary with reference to the primary to thereby shift the phase relation of one set of filter circuits with reference to another.

In conclusion, it is apparent that I have provided a relatively simple construction and arrangement of filter circuits with means for adjusting the same, in a manner such as to suppress and substantially eliminate interfering frequencies covering a substantial band above and below a desired signal wave, and due to the tuning controller I provide I am able to maintain this relationship between the incoming signal wave and the frequency bands to be suppressed throughout the entire range of my apparatus.

Having thus described my invention, what I claim as new is:

I. In a radio receiving circuit, a signal circuit including a tuned primary input coil and an untuned output coil, said coils being loosely inductively coupled, a first tuned secondary filter circuit closely inductively coupled with said input coil, a second tuned secondary filter circuit closely inductively coupled with said untuned output coil, and means for simultaneously tuning all of said tuned circuits to render the signal circuit resonant to an incoming signal while maintaining the first and second filter circuits respectively resonant to frequencies above and below the signal frequency.

2. In a radio receiving circuit, a signal circuit including a tuned primary input coil and an untuned output coil, said coils being loosely inductively coupled, a first tuned secondary filter circuit closely inductively coupled with said input coil, a second tuned secondary filter circuit closely inductively coupled with said output coil, and means for relatively varying the degree of inductive coupling between the input and output coils and between the filter circuits and the respective input and output coils.

3. In a radio receiving circuit, a signal circuit including a timed primary input coil and an untuned output coil, said coils being loosely inductively coupled, a first tuned secondary filter circuit closely inductively coupled with said input coil, a second tuned secondary filter circuit closely inductively coupled with said output coil, means for simultaneously tuning all of said tuned circuits to render the signal circuit resonant to an incoming signal while maintaining the filter circuits respectively resonant to frequencies above and below the signal frequency, and means for relatively varying the degree of inductive coupling between the input and output coils and between the filter circuits and the respective input and output coils.

4. In a radio receiving circuit, a signal circuit including a tuned primary input coil and an untuned output coil, said coils being loosely inductively coupled, a first tuned secondary filter circuit inductively coupled with said input coil and having a resonant frequency below the resonant frequency of the input coil at all times, a second tuned secondary filter circuit inductively coupled with the output coil and having a resonant frequency above that of the input circuit at all times, and means for tuning the input circuit to resonance with a desired signal frequency while maintaining the filter circuits respectively resonant to frequencies above and below that of the signal frequency.

5. In a radio receiving circuit, a tuned primary signal circuit, a tuned secondary filter circuit inductively coupled with said signal circuit, a second tuned filter circuit inductively coupled with the signal circuit and said first mentioned filter circuit, said filter circuits being resonant to frequencies respectively above and below that of the signal circuit at all times, means for simultaneously tuning the signal circuit and said filter circuits to render the signal circuit resonant to a desired signal frequency while maintaining the filter circuits resonant to frequencies respectively above and below that of the signal frequency, and a pair of inductively coupled tuned filter circuits loosely coupled with said signal circuit and having frequencies respectively above and below that of the signal circuit at all times.

6. A filter net-work comprising a circuit including a tuned primary coil and an untuned primary coil connected in series, a tuned secondary trap circuit inductively coupled to the tuned primary coil, a tuned seoondarytrap circuit inductively coupled to the untuned primary coil, and two additional tuned trap circuits inductively coupled to each other, one of said last mentioned tuned trap circuits being also inductively coupled to the tuned primary coil, and the other of said two additional trap circuits being inductively coupled to said untuned primary coil.

'7. A filter net-work comprising a circuit including a tuned primary coil and an untuned primary coil connected in series, a tuned secondary trap circuit inductively coupled to the tuned primary coil, a tuned secondary trap circuit inductively coupled to the untuned primary coil, said second tuned trap circuit being inductively coupled to the tuned primary coil, and said first tuned trap circuit being inductively coupled to said untuned primary coil.

8. A filter network comprising a series inductance circuit including a timed primary circuit and an untuned primary coil, a first tuned secondary trap circuit inductively coupled to said tuned primary circuit, a second tuned secondary trap circuit inductively coupled to said untuned primary coil, a third tuned trap circuit inductively coupled to the tuned primary and to said first tuned trap circuit, and a fourth tuned trap circuit inductively coupled to the third tuned trap circuit and to the first tuned trap circuit and to the untuned primary coil.

EMMI'IT L. MOCLURIE. 

